氮化硅介质薄膜内应力的实验研究

研究了等离子体增强化学气相沉积氮化硅介质薄膜的内应力。采用钠光平面干涉测量了氮化硅薄膜内应力,通过改变薄膜沉积时的工艺参数,考察了反应气体流量化、沉积温度、射频功率密度等因素对氮化硅薄膜内应力的影响。在此基础上,对氮化硅介质薄膜本征应力的形成机制进行了分析讨论。     

氮化硅介质薄膜内应力的实验研究

研究了等离子体增强化学气相沉积氮化硅介质薄膜的内应力。采用钠光平面干涉测量了氮化硅薄膜内应力,通过改变薄膜沉积时的工艺参数,考察了反应气体流量比、沉积温度、射频功率密度等因素对氮化硅薄膜内应力的影响。在此基础上,对氮化硅介质薄膜本征应力的形成机制进行了分析讨论。     

类金刚石薄膜内应力的测试

采用射频-直流等离子增强化学气相沉积法制备出类金刚石薄膜,用弯曲法测定薄膜的内应力。结果表明,类金刚石薄膜中存在1～4.7GPa的压应力,沉积工艺对薄膜的内应力有很大的影响,薄膜的内应力随极板负偏压的升高而降低,陆C_2H_2气体含量的增加而增大。     

类金铡石薄膜内应力的测试

采用射频－直流等离子增强化学气相沉积法制备出类金刚石薄膜，用弯曲法测定薄膜的内应力。类金刚石薄膜中存在１－４．７ＧＰａ的压应力，沉积工艺对薄膜的内应力有很大影响，薄膜的内应力随极板负偏压的升高而降低，随Ｃ２Ｈ２气体一的增加而增大。     

厚度对DLC薄膜内应力的影响研究

采用ECR微波等离子体增强化学气相沉积的方法于C1H2/H2/Ar2等离子环境中在单晶Si(111)晶面上制备了不同厚度的DLC膜样品,研究了薄膜的厚度随沉积时间的变化及薄膜的硬度、内应力随厚度的变化关系.结果表明,在沉积时间变化范围内,厚度与沉积时间基本呈线性关系,沉积速率可达80nm/min;制备态样品存在的内应力...     

高速钢基体离子注氮对c-BN薄膜制备的影响研究

采用射频磁控溅射法在离子注氮的高速钢基体上沉积制备c-BN薄膜,主要研究离子注氮层对c-BN薄膜相结构和内应力的影响;采用各种现代分析方法对沉积的薄膜进行了表征分析,包括傅立叶红外光谱(FTIR)、X射线光电子能谱(XPS)和原子力显微镜(AFM)等分析方法;试验结果表明:高速钢基体上离子注氮有利于立方氮化硼含量的提高和薄膜内应力的降低,同时注氮处理的高速钢基体上沉积的薄膜表面形貌平整,结晶性较好.并采用X射线衍射分析(XRD)对高速钢基体的离子注氮层进行了相结构分析,探索研究了离子注氮层对c-BN薄膜生长的影响.     

脉冲多弧离子镀制备类金刚石薄膜的特性

利用脉冲多弧离子镀技术在硅基底上沉积出非晶的类金刚石薄膜。薄膜的折射率为 2 8左右 ;沉积速率与主回路电压以及脉冲频率有关 ;膜层致密 ,但薄膜表面不光滑 ;薄膜电阻率接近 1× 10 10 Ω·cm数量级 ;薄膜的硬度及附着力与基底温度、主回路电压以及脉冲频率密切相关 ;薄膜中存在强的内应力 ,内应力是影响膜层附着力的主要因素。     

类金刚石薄膜的摩擦学特性及磨损机制研究进展

类金刚石薄膜已显示了重要的摩擦学应用价值,其中化学气相沉积的类金刚石薄膜(DLC)具有膜层致密、厚度均匀、摩擦学性能优良等特点成为广泛采用的一种沉积方法.本文介绍了气源成分、基体材料、摩擦环境、摩擦对偶、载荷及速度对化学气相沉积制备类金刚石薄膜的摩擦学特性的影响,概述了其摩擦磨损机理,同时探讨了进一步研究工作的方向.     

多弧离子镀制备硬质梯度薄膜技术

介绍了多弧离子镀在金属陶瓷表面沉积硬质梯度薄膜的技术,用X射线衍射法对表面形成的薄膜进行了物相分析,并对材料的金相显微组织、显微硬度、抗弯强度以及膜与基体的结合力进行了测试和分析.结果表明:多弧离子镀处理能在金属陶瓷表面形成硬质梯度薄膜,膜与基体的结合力良好,表面硬度大大提高,而材料的抗弯强度却没有发生变化.     

氧化铝基体表面预处理对金刚石薄膜生长的影响

采用微波等离子体化学气相沉积方法,在经不同预处理的氧化铝衬底上沉积金刚石薄膜.用X射线衍射仪、激光拉曼光谱仪、扫描电镜(SEM)对所得薄膜的成分、物相纯度和表面形貌进行表征,比较不同的预处理方式对金刚石薄膜生长的影响.结果表明,基体表面经过熔融碱腐蚀后形成薄膜的膜基结合良好且膜材质量最佳,但表面平整度较低;而基体只经金刚石微粉乙醇悬浊液超声处理则在沉积时金刚石容易成膜,且结构要更为致密;在经过酸腐蚀的基体上沉积金刚石薄膜时,容易在薄膜与基体之间先形成过渡层,而后才进行金刚石薄膜的沉积.所得结果表明熔融碱腐蚀处理是获得电学应用氧化铝基金刚石薄膜复合材料的最适宜的基体表面预处理.     

The nature of stresses in hot-filament chemical vapour deposited diamond thin films on WC substrates

The nature of film stresses in hot-filament chemical vapour deposited (HFCVD) diamond thin films on tungsten carbide substrates, is reported. Commercial WC substrates were subjected to various surface treatments. Subsequently, they were coated with a diamond film and examined for stresses using X-ray diffraction. All but one of the stress measurements indicated various levels of compressive stresses in the film and at the film–substrate interface. These stresses are compared with those obtained by other researchers. Intrinsic film stresses were also computed for diamond films and found to be tensile. WC drills, of 0.125 in. diameter, were also diamond coated and the stress levels measured along drill flanks and flutes. Significant variations were found in these stresses, and the results were analysed from a film–substrate adhesion perspective.     

Influence of WC-Co substrate pretreatment on diamond film deposition by laser-assisted combustion synthesis

The quality of diamond films deposited on cemented tungsten carbide substrates (WC-Co) is limited by the presence of the cobalt binder. The cobalt in the WC-Co substrates enhances the formation of nondiamond carbon on the substrate surface, resulting in a poor film adhesion and a low diamond quality. In this study, we investigated pretreatments of WC-Co substrates in three different approaches, namely, chemical etching, laser etching, and laser etching followed by acid treatment. The laser produces a periodic surface pattern, thus increasing the roughness and releasing the stress at the interfaces between the substrate and the grown diamond film. Effects of these pretreatments have been analyzed in terms of microstructure and cobalt content. Raman spectroscopy was conducted to characterize both the diamond quality and compressive residual stress in the films.     

Nano-crystalline CVD diamond films deposited on cemented carbide using high current extended DC arc plasma process

Nano-crystalline diamond (NCD) films have been grown on cemented carbide substrates by high current extended DC arc plasma process using Ar/H₂/CH₄ gas mixture at low gas pressure. The plain view and cross section of films are characterized with scanning electron microscopy. A uniform and smooth surface morphology of NCD thin films is observed. Raman spectroscopy has been used to investigate purity of the NCD films. Experimental results on the synthesis and characterization of the NCD films on cemented carbide substrates are discussed in this article.     

The stress in ion-plated HfN and TiN coatings

The X-ray diffraction sin²ψ method was used to determine the state of stress in HfN and TiN coatings made by ion plating onto various substrates. Some subsidiary measurements on chemically vapour-deposited coatings are also included. In many cases the results show deviations from the simple linear behaviour: examples of both curvature (stress gradients perpendicular to the surface) and ψ splitting (shear stress effects) are found. Both the chemically vapour-deposited samples show the latter effect together with compressive and tensile stresses in the HfN and TiN coatings respectively in the plane of the coating. The ion-plated coatings are all under compressive stress. On stainless steel the stress level is high owing to a change in the stress distribution in the steel during the ion plating process. The stress in the coatings on cemented carbide and high speed steel, which should be unaffected by the coating process, falls as the coating thickness increases; this appears to be related to a microstructural change in the coating.     

A REVIEW OF THE CHEMICAL VAPOR DEPOSITION (CVD) OF THE REFRACTORY COMPOUNDS OF TITANIUM - A UNIQUE FAMILY OIF COATINGS

This paper is a review of a unique family of refractory compounds comprising the boride, carbide and nitride of titanium. These materials are characterized by high hardness, high wear resistance and chemical inertness. They are obtained as coatings by chemical vapor deposition (CVD) on a variety of substrates such as tool steel, cemented carbides, graphite and many others. Promising deposition techniques are plasma-CVD and metallo-organic CVD. Major applications of these coatings are found in wear, erosion and corrosion protection and in cutting tools     

Pressure dependence of morphology and phase composition of SiC films deposited by microwave plasma chemical vapor deposition on cemented carbide substrates

SiC films were deposited on cemented carbide substrates by employing microwave plasma chemical vapor deposition method using tetramethylsilane (Si(CH₃)₄) diluted in H₂ as the precursor. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and scratching technique were used to characterize morphology, composition, phases present and adhesion of the films. Experimental results show that the deposition pressure has great influence on morphologies and phase composition of the films. In sequence, SiC films with a cauliflower-like microstructure, granular films with terrace-featured SiC particles coexisting with Co₂Si compound and clusters of nanometer SiC nanoplatelets appear as a function of the deposition pressure. In terms of plasma density and substrate temperature, this sequential appearance of microstructures of SiC films was explained. Adhesion tests showed that among the three types of films studied, the films with the terrace-featured SiC particles have relatively higher adhesion. Such knowledge will be of importance when the SiC films are used as interlayer between diamond films and cemented carbide substrates.     

Residual stresses in titanium nitride thin films deposited by direct current and pulsed direct current unbalanced magnetron sputtering

This work presents a study on the effect of deposition parameters on the residual stresses developed in titanium nitride (TiN) thin films deposited onto cemented carbide (WC-Co) substrates. Depositions were conducted by reactive unbalanced magnetron sputtering of a single titanium target. Six different conditions were selected, varying parameters such as bias (0, − 50 or − 100 V), power applied to the target (direct current or pulsed direct current) and, in the cases where substrate bias was zero, substrate condition (ground or floating). Pulsed power was applied at a frequency of 50 kHz and with a reverse pulse time of 1 μs. Residual stresses were evaluated through X-ray diffraction, using the sin²ψ method. Results confirmed the effect of substrate bias on the residual stresses of thin films. Additionally, it was possible to observe that by pulsing the power to the target, residual stress varies as a consequence of the increased ion energy.     

Study on adhesion and wear resistance of multi-element (AlCrTaTiZr)N coatings

Multi-element (AlCrTaTiZr)N films were deposited on cemented carbide and M2 steel substrates by reactive RF magnetron sputtering. Prior to nitride film deposition, an interlayer between the film and the substrate was introduced to improve adhesion property. The influence of interlayer materials (Ti, Cr, and AlCrTaTiZr alloy) and interlayer thickness (0–400 nm) on the adhesion and tribological properties of films was investigated. In this study, the nitride film deposited at R_N = 20% exhibited the highest hardness (35.2 GPa) and the lowest residual compressive stress (? 1.52 GPa), and was prepared as the top layer for further testing. The interlayer materials can effectively improved the film adhesion onto the cemented carbide substrates, and the adhesive failure was not observed even under the normal load of 100 N. For M2 steel substrates, only the Cr interlayer can slightly improve the film adhesion, and the cohesive and adhesive failure can be found at relatively lower applied load. The optimal interlayer thickness was 100–200 nm for the 1 µm-thick (AlCrTaTiZr)N film and can be related to the stress evolution. The friction coefficient and wear rate for the (AlCrTaTiZr)N film were 0.82 and 4.9 × 10^? 6 mm³/Nm, respectively, and almost kept constant under different interlayer materials and thickness. The worn-through event of the nitride film during tribological test occurred easily owing to its poor adhesion behavior, and can be improved by interlayer additions.     

Formation of thick titanium carbide films by the hollow cathode discharge reactive deposition process

Thick titanium carbide films were successfully deposited on mild steel sheets using a hollow cathode discharge reactive deposition process. Methane, ethylene and acetylene were used as reactant gases during the titanium evaporation and the substrates were either negatively biased or grounded. The deposited films were characterized by microhardness measurements, X-ray diffraction, Auger electron spectroscopy and secondary ion mass spectrometry. The results are discussed with regard to deposition conditions and chemical composition.     

Improvements in reliability and serviceability of cemented carbides with wear-resistant coatings

Typical defects in microstructure at a surface-coating interface in chemical vapor deposition coated cemented carbides are described. Results on applying new technologies developed to improve reliability and serviceability of coated cemented carbides are presented. Using WC-based cemented carbide substrates with a uniform, fine microstructure etched before coating eliminates various defects at the surface-coating interface. This results in improvement in serviceability and reliability of the coated cemented carbides in metal-cutting.